So let's drill down into these statements, as this is probably a blue print for common thought process.
Company offers sick time for employees to use because - people get sick. Sidebar - not everyone gets sick at the same rate or take time off for being sick. Fact.
You can't just have willy nilly sick time - it would be abused and hurt employee morale. So you set a number of days annually for sick time. Sidebar - you have a percentage of employees who just always seems to hit that number of sick days per year, meanwhile you have some who rarely use sick days. Employees know who does what.
So to try to be fair and compensate the good employees, you either carry over or set up a system where sick days are paid out at retirement or at least reward people for not frivolously using sick time. Sidebar - some employers try to get doctor's notes for absences - Bad idea, so you force your employees into a healthcare system that is already expensive and understaffed, even if they have bad cold or the common flu.
So a company may be struggling along to make a profit, pay employees, put money back into the business, etc. And you have employees now, who may have been there for 20-30 years who bank out hundreds of hours of sick time and there's this financial hit to the company when that retiree goes out the door. The company has to account for this in budgeting purposes because it's a potential expense.
These are just a few of the HR/ accounting nighmares that go into something as simple as people who just "take" sick days.